What are the possible causes of dysmenorrhea in a female of reproductive age?

Causes of Dysmenorrhea in Reproductive-Age Women

Dysmenorrhea is classified into primary (no identifiable pelvic pathology) and secondary (underlying pelvic disease), with primary dysmenorrhea caused by excessive prostaglandin production leading to painful uterine contractions, while secondary dysmenorrhea results from conditions such as endometriosis, adenomyosis, uterine fibroids, or pelvic inflammatory disease. 1, 2

Primary Dysmenorrhea

Primary dysmenorrhea occurs in the absence of macroscopically identifiable pelvic pathology and affects over 50% of menstruating women. 1, 3

Pathophysiology

• Excessive prostaglandin production and release from the endometrium is the primary mechanism, causing increased uterine tone and stronger, more frequent uterine contractions that restrict blood flow. 1, 2
• The cyclooxygenase pathway produces increased prostanoids, particularly prostaglandins (PGs), which lead to production of anaerobic metabolites that stimulate pain receptors. 2
• Endometrial inflammation contributes to the increased prostaglandin release. 4

Clinical Characteristics

• Pain is suprapubic and spasmodic, typically starting at or shortly after menarche. 1
• Pain lasts 48-72 hours during menstrual flow, most severe during the first or second day of menstruation. 1
• Associated symptoms may include nausea, vomiting, diarrhea, headache, and fatigue. 1, 3

Secondary Dysmenorrhea

Secondary dysmenorrhea is pelvic pain associated with underlying pelvic pathology. 5

Gynecologic Causes

Endometriosis is a major cause, characterized by endometrium-like tissue outside the uterus that induces chronic inflammation, chronic pelvic pain, and dysmenorrhea, affecting 2-10% of women of childbearing age. 6

Adenomyosis causes dysmenorrhea through endometrial tissue within the myometrium. 4, 5

Uterine fibroids (leiomyomas) affect 10-30% of women of reproductive age and are independently associated with dysmenorrhea, with greater risk in women of sub-Saharan African ancestry. 6

Pelvic inflammatory disease from sexually transmitted infections causes secondary dysmenorrhea through inflammatory damage to pelvic structures. 6, 1

Ovarian cysts can cause cyclic pelvic pain and dysmenorrhea. 1

Cervical stenosis restricts menstrual flow, causing painful uterine contractions. 1

Congenital malformations of the uterus (such as bicornuate uterus or uterine septum) can cause secondary dysmenorrhea. 1

Pelvic adhesions from prior surgery or infection restrict normal pelvic anatomy and cause pain. 1

Intrauterine Device (IUD)

• IUD use causes dysmenorrhea through excessive prostaglandin production and release, though this is readily controlled with prostaglandin inhibitors. 1

Endocrine and Systemic Causes

Polycystic Ovary Syndrome (PCOS) affects 4-8% of women and is associated with menstrual irregularities including dysmenorrhea, characterized by hyperandrogenism, irregular periods, and polycystic ovarian morphology. 6, 7

Thyroid dysfunction (both hypothyroidism and hyperthyroidism) can cause menstrual irregularities and dysmenorrhea by affecting the hypothalamic-pituitary-ovarian axis. 7

Hyperprolactinemia accounts for approximately 20% of menstrual disorders and can cause dysmenorrhea through disruption of normal hormonal cycling. 7

Critical Diagnostic Distinctions

When to Suspect Secondary Dysmenorrhea

• Onset of dysmenorrhea after age 25 years suggests secondary causes rather than primary dysmenorrhea. 2
• Progressive worsening of pain over time indicates possible endometriosis or adenomyosis. 4
• Pain that begins before menstruation or persists after menstrual flow ends suggests secondary causes. 4
• Dyspareunia, chronic pelvic pain, or infertility accompanying dysmenorrhea strongly suggests endometriosis. 6
• Failure to respond to NSAIDs and hormonal contraception after 6 months of compliant use warrants evaluation for secondary causes. 1, 2

Key History Elements to Elicit

• Age at menarche and onset of dysmenorrhea - primary dysmenorrhea typically starts at or shortly after menarche. 1
• Timing, duration, and severity of pain relative to menstrual cycle. 6
• Sexual history including STD exposure to assess for PID risk. 6
• Previous pelvic surgery or infections that could cause adhesions. 6
• Associated symptoms including dyspareunia, dyschezia, or infertility suggesting endometriosis. 6

Physical Examination Findings

• Normal pelvic examination supports primary dysmenorrhea diagnosis. 2
• Pelvic or adnexal tenderness, masses, or nodularity suggests secondary causes requiring further evaluation. 6
• Uterine enlargement may indicate fibroids or adenomyosis. 6
• Fixed, retroverted uterus or cul-de-sac nodularity suggests endometriosis. 6

Common Pitfalls

• Do not assume all dysmenorrhea in young women is primary - endometriosis can present in adolescence and early diagnosis prevents progression. 4
• Do not delay laparoscopy beyond 6 months if prostaglandin inhibitors are ineffective, as this may indicate undiagnosed endometriosis. 1
• Recognize that untreated dysmenorrhea can lead to hyperalgesic priming, predisposing to chronic pelvic pain and reducing life course potential. 4